Posterior capsular opacification (PCO) is a common long-term complication of cataract surgery. During cataract surgery, the central anterior lens capsule is removed and the natural lens replaced with an artificial intraocular lens. The posterior lens capsule remains intact. After surgery, viable epithelial cells of the natural lens may remain in the lens capsule equator. These cells can migrate across the inner surface of the posterior capsule, causing it to opacify. The effect, i.e. PCO, is similar to a cataract and for this reason is sometimes called “secondary cataract”. PCO is age-related, occurring more in children rather than adults.
The standard treatment for PCO is neodymium: yttrium-aluminium-garnet (Nd-YAG) laser posterior capsulotomy. The laser is used to create an opening in the centre of the posterior capsule, to produce a clear area for light to reach the retina. Although the procedure is non-invasive, complications such as retinal detachment and lens damage may arise.
EP-A-0962196 describes an intraocular lens wherein the haptics are shaped such that, in a first stage of compression, the proximal part of the haptic can be fully compressed; and in a second stage, the distal part of the haptic can be compressed, to provide a lens that is eventually resistant to haptic failure.
A number of lenses for the prevention of PCO have been proposed, but on the whole, little if any reduction in PCO has been achieved. There still exists the need for an intraocular lens which is effective at reducing PCO.